APPENDIX B 291 



or less confidence in the potent arsenic compound, 

 * atoxyl ' (a sodium salt of paramidophenylarsenic 

 acid), and all agree that it is the best drug yet known. 

 More recently its use has been combined with that of 

 bichloride of mercury, and the results seem to promise 

 well. There seems to be no question that the disease 

 may be held in check for a time by the use of atox}-], 

 and it is possible that complete cures have been ob- 

 tained by this means ; but relapses are exceedingly 

 common. In any case the treatment must be con- 

 tinued for a long time and energetically, until the 

 patient has been free from all symptoms for a long 

 period and no sign of trypanosomes can be found (by 

 injection into susceptible animals) in the blood. The 

 attempts that have been made in serum-therapy have 

 hitherto been failures. 



It is to the prevention of sleeping sickness that the 

 most strenuous measures must be directed at present ; 

 but even here there are very serious drawbacks in our 

 ignorance of the complete life-histories of the tsetse- 

 fly and the trypanosoma, and of the exact relationship 

 between the parasite and its carrier. Nor do we know 

 what are the normal hosts of the trypanosome under 

 natural conditions. It is true that a great deal can be 

 done in this direction. The tsetse-fly lives near 

 water; villages must, therefore, be moved away from 

 the banks of rivers and lakes. The fly requires ran k 

 vegetation ; much can be done (as has been done 

 successfully at Entebbe) in the way of clearing the 

 bushes and undergrowth from the lake-shore. But 

 there still remains the absolute necessity of following 

 the waterways for purposes of transport, fishing, etc., 

 and in these occupations the natives must inevitably 

 be exposed to the bites of tsetse-flies. If they could 

 be induced to wear some sort of light garment, the}' 

 would obtain a certain measure of protection ; but 



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